JPH04324618A - Formation of resist pattern - Google Patents

Abstract

PURPOSE:To dissolve such problems that a resist is left in a groove-like section on a base substrate due to insufficient exposure and that the dimension control of an opening at a large level-difference section on the base substrate becomes difficult. CONSTITUTION:After a positive resist 101 is selectively formed on a pattern forming substrate 102, a negative resist 103 is formed on the entire surface of the substrate 102. Then the resist 103 is etched until the pattern top 104 of the resist 101 crops out. After etching the resist 103, only the positive resist 101 is removed by using a negative resist developing solution having a small selection ratio against the positive resist 101.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method in the manufacture of semiconductor integrated circuit devices.

0002

[Prior Art] Currently, as semiconductor integrated circuit devices become more highly integrated, resist patterns, which can be said to represent full-scale circuit designs on a substrate, are required to be smaller and more precise. There is.

Conventionally, as a method for forming micropatterns in the manufacturing method of semiconductor integrated circuit devices, there is a method disclosed in Japanese Patent Laid-Open No. 55
The method described in Japanese Patent No. 11335 has been proposed. FIGS. 2A and 2B are process cross-sectional views for explaining the prior art.

In FIG. 2(A), a pattern forming substrate 2
A positive resist 202 is applied on the photoresist 01, and an exposure mask 203 is placed on top of the positive resist 202. The white part of the exposure mask 203 is the exposure area through which light passes,
The black areas are unexposed areas that do not allow light to pass through.

FIG. 2B is a cross-sectional view of a resist pattern formed after exposure and development.

As shown in the above, the conventional method for obtaining a micropattern is to apply a positive resist in which the unexposed areas remain as resist, expose only the area to be opened, and then develop the entire surface to form a micropattern. I was getting . This is because a positive resist allows formation of a finer pattern than a negative resist, in which the exposed portion remains as a resist.

[0007]

[Problems to be Solved by the Invention] However, the method described above has several problems. This is shown in Figure 3 (
This will be explained using a) and (b). In addition, Figure 3(a) and (
b) is a cross-sectional view when forming a resist pattern of a semiconductor device according to a conventional technique.

First, in a part with a large level difference between the base layers as shown in FIG. At least in the substrate part, the dimension d2 of the thicker resist film is smaller than the dimension d1 of the thinner resist film, making it difficult to control the dimensions.

Second, as shown in FIG. 3(b), in the groove-shaped portion of the underlying substrate 301, the positive resist may not be completely removed due to insufficient exposure, and a residual resist 303 may remain. .

The present invention solves the above-mentioned problem that it is difficult to control the aperture size in areas with large step differences in the base, and the problem that resist remains in groove-like areas of the base. It is an object of the present invention to provide a resist pattern forming method in which the opening size is determined at the upper part of the pattern and there is no resist remaining due to insufficient exposure.

[0011]

[Means for Solving the Problems] The present invention provides a pattern forming method in a method of manufacturing a semiconductor integrated circuit device.
A first resist material made of, for example, a positive resist is left only in the part of the substrate where a pattern is to be formed where an opening is desired, and a second resist material made of, for example, a negative resist is applied to the entire surface and exposed. A pattern is obtained by removing the negative resist and removing the first resist material using an etching solution that has a small selectivity with the first resist material and a high selectivity with the second resist material. It is.

Alternatively, a developer for the second resist material is used as the etching solution which has a small selectivity with the first resist material and a large selectivity with the second resist material.

[0013]

[Operation] According to the method of the present invention, after securing the area to be opened with the first resist material, the second resist material that becomes the original resist pattern is applied, and then the first resist material is removed. , the second resist material is not present in the opening.

Furthermore, the shape of the opening is determined by the shape of the first resist material that is initially formed.
When a positive resist is used as the resist material, the dimension of the first resist material on the resist surface becomes the minimum dimension of the opening, and the dimension inside the opening becomes larger.

[0015]

[Example] Process cross-sectional views of an example of the present invention are shown in FIGS.
Shown in (D).

First, as shown in FIG. 1A, a pattern forming substrate 102 is coated with a positive resist 101 of about 10,000 to 12,000 Å, and exposed and developed so that the resist remains only in the areas that will be opened in the subsequent process. A first resist material is formed. After development, the resist film thickness of the resist pattern 101 is 8000 to 10000.
It has decreased to about Å.

Next, as shown in FIG. 1(B), 5000
A negative resist 103 of about 6000 Å is coated as a second resist material, and the entire surface is exposed. Since the exposed portion of the negative resist becomes a resist film, the negative resist 103 is formed on the entire surface of the pattern forming substrate.

Next, in order to expose the pattern upper part 104 of the positive resist 101 on the surface, as shown in FIG.
Etch approximately 0 to 2000 Å.

Next, as shown in FIG. 1(D), processing is performed using a negative resist developer. When a developer having a small selection ratio with respect to the positive resist is used as the negative resist developer, the negative resist 103 remains since the entire surface has been exposed, and only the positive resist 101 is etched and removed, forming a mask pattern.

According to this method, the positive resist 101 in the opening is reliably removed by etching.
Resist will not remain in the grooves due to insufficient exposure.

[0021] Furthermore, when using anisotropic etching,
The opening size is determined by the size of the upper part of the resist pattern. Therefore, as can be seen by comparing FIG. 3A showing the pattern size determination position according to the prior art and FIG. 4 showing the pattern size determination position according to the present invention, the size d1 that would have occurred in the conventional technology In the embodiment of the present invention, the problem that d2 and d2 are different becomes the dimension d3 regardless of the step,
Difficulties in dimensional control caused by differences in actual resist film thickness due to step differences are resolved.

The present invention is not limited to the above-mentioned embodiments, but after forming the second resist material, development and surface etching are performed, and the first resist material has a high selectivity with respect to the second resist material.
The first resist material may be etched away using an etching solution having a small selectivity with respect to the resist material.

Using the second resist material formed as described above as a mask, the materials to be etched, such as an insulating layer and a wiring layer, are patterned.

Furthermore, the present invention can also be used when it is desired to implant impurities into a substrate or the like. For example, M in the board
If the present invention is used as a mask for forming source/drain regions of an OS transistor, impurity regions with excellent controllability can be formed.

[0025]

As described above in detail, according to the method of the present invention, after the formation of the second resist material, the opening has a high selectivity with respect to the second resist material and the first resist material. Since only the first resist material is removed and opened using an etching solution with a low selection ratio, there is no unexposed positive resist remaining in the groove-shaped portion as in the conventional method, and the opening can be reliably performed.

Furthermore, by using a positive resist as the first resist material, using a negative resist as the second resist material, and using a negative resist developer having a small selectivity with the positive resist as the etching solution, it is possible to Developing the resist and removing the positive resist can be done at the same time, simplifying the process.

According to the method of the present invention, the dimensions at the upper part of the opening can be made constant. Even if the positive resist takes on a tapered shape due to the influence of a level difference in the base, and the dimensions inside the opening vary, the dimension will not become smaller than the dimension at the top of the opening. When performing anisotropic etching, the dimensions are determined at the upper part of the opening, making it easier to control the dimensions.

When used as a mask for ion implantation into a semiconductor substrate, dimensional control becomes easy as in the case of anisotropic etching.

[Brief explanation of drawings]

FIG. 1 is a process sectional view of an embodiment of the present invention.

FIG. 2 is a process sectional view of the prior art.

FIG. 3(a) is a cross-sectional view showing a pattern size determination position according to the prior art. (b) A cross-sectional view when forming a resist pattern according to the conventional technique.

FIG. 4 is a cross-sectional view showing the pattern size determination position of the present invention during formation of a resist pattern.

[Explanation of symbols]

101 Positive resist 102 Pattern-forming substrate 103 Negative resist

Claims (5)

[Claims] 1. A method for forming a first region in which no resist material is present and a second region in which a pattern made of a resist material is present on a pattern forming substrate, comprising: (a) applying a first resist to the first region; (b) forming a second resist material in the second region; (c)
) a step of removing the first resist material with an etching solution having a high selectivity with the second resist material and a small selectivity with the first resist material. 2. Forming on a semiconductor substrate a first region where no resist material exists and a second region where a pattern made of the resist material exists, and using the resist material as a mask,
As a method of patterning the material to be etched, (a)
forming a first resist material in the first region;
b) forming a second resist material in the second region; and (c) etching the first resist material using an etching solution that has a high selectivity with the second resist material and a small selectivity with the first resist material. (d) etching the first region using the second resist material as a mask. 3. Forming on a semiconductor substrate a first region in which no resist material exists and a second region in which a pattern made of the resist material exists, and using the resist material as a mask,
As a method of implanting ions into the semiconductor substrate, (a)
forming a first resist material in the first region;
b) forming a second resist material in the second region; and (c) etching the first resist material using an etching solution that has a high selectivity with the second resist material and a small selectivity with the first resist material. (d) implanting ions into the first region using the second resist material as a mask. 4. A method for forming a first region in which no resist material is present and a second region in which a pattern made of a resist material is present on a pattern forming substrate, the method comprising: (a) applying a first resist to the first region; (b) forming a second resist material different from the first resist material in the first and second regions;
(c) forming the second resist material thinner than the first resist material in the first region; (d) removing the second resist material present on the surface of the material until at least the first resist material is exposed on the surface; (d) removing the second resist material existing on the surface of the material; A resist pattern forming method comprising the step of removing a first resist material with an etching solution having a small selectivity to the resist material. 5. In the resist pattern forming method according to claim 1 or 4, the pattern forming method according to claim 2, or the ion implantation method according to claim 3, the first resist material is a positive resist; A resist pattern forming method or a pattern forming method characterized in that a negative resist is used as the resist material in step 2, a developing solution for the negative resist is used as the etching solution, and a developing step of the negative resist and a step of removing the positive resist are performed simultaneously. Or ion implantation method.